Updated project metadata. Initiation and completion of DNA replication has a major impact on chromatin, but how core chromatin processes are cell cycle regulated in somatic cells remains poorly understood. To address this question we conducted a quantitative proteomics study that took advantage of an analogue sensitive mutation in Cdk1 (cdk1as), which allows for rapid and highly specific inactivation of Cdk1 by the bulky ATP analogue 1NMPP1. Neither Cdk1 nor Cdk2 are required for S-phase progression, while inactivation of Cdk1 in Cdk2 knock-out cells causes a complete block of DNA replication initiation and S-phase progression. Here we compared chromatin fractions obtained from cdk1as and cdk1as/cdk2-/- cells two hours after Cdk1 inactivation. Statistical analysis of these four independent experiments (including 2 label swaps) identified 135 proteins that showed a significant change in SILAC ratio among a total of 2402 proteins quantified in at least three experiments. This approach led us to discover a novel functional interplay between interphase Cdks and the chromatin association of a variety of novel candidate proteins such as Cdk1 itself, the APC/C regulatory subunit cdc20, the PP4 regulatory subunit Smek2, the helicase FUBP1 and the PHD domain-containing zinc finger protein PHF6.